The field of the present invention is building construction hardware for mounting components such as utilities.
Building construction frequently uses steel web joists. Such devices employ two beams. The beams are mutually parallel and spaced apart to create a large moment of inertia for the joist. Cord elements extend at angles between the two so the beams will act as one in bending. Each beam includes a set of two elongate angle elements which are also mutually parallel. The cord elements extend for anchoring to between the elongate angle elements which form a cord space to receive the elements. Each angle element includes two legs extending at a right angle to one another, a first leg which is parallel with the first leg of the other angle element to define the cord space and a second leg extending in the opposite direction from the second leg of the other angle element to generally define a plane. The two first legs extend to define parallel edges.
Seismic adapters have been associated with such steel web joists by positioning two flat washers about one of the sets of angle elements. One washer lies in the plane of the second legs such that it extends across the cord space in juxtaposition with the second legs. A second washer is arranged to abut against the parallel edges of the first legs, also extending across the cord space. A threaded stud extends between the washers with a nut or bolt head retaining the first washer in juxtaposition with the second legs. The threaded stud extends beyond the second washer to accommodate attachment hardware. The entire assembly is then clamped to the joist by threading a nut up snug against the attachment hardware and, in turn, the second washer. Although this system is structurally sound, there is some prospect of limited lateral movement of the attachment.
The present invention is directed to a seismic suspension system. The system comprises a steel web joist including a beam with two angle elements. Each angle element includes a first leg and a second leg, the first legs being parallel with a cord space therebetween and the second legs extending in opposite directions. An anchor plate having a hole therethrough is positionable across the cord space into juxtaposition with the second legs of the beam. An engagement plate having a hole therethrough abuts up against the parallel edges of the first legs of the beam. A threaded stud extends from the anchor plate to and beyond a hole in the engagement plate. The engagement plate is able to interlock with the first legs.
In a first separate aspect of the present invention, the engagement plate includes a flat anchor portion and upstanding engagement portions to either side of the flat anchor portion. The engagement portions have distal edges with an engagement profile for interlocking engagement with the beam. This greatly restricts or eliminates any lateral movement of the adapter.
In a second separate aspect of the present invention, the engagement plate includes distal edges with tongues extendible to between the parallel legs of the steel web joist beam for interlocking engagement. The tongues may be tapered to accommodate variations in the cord space. Shoulders to either side of each tongue may abut against the edges of the legs.
Accordingly, it is an object of the present invention to provide an improved selsmic suspension system. Other and further objects and advantages will appear hereafter.